Sealing ring

ABSTRACT

There is disclosed a sealing ring of resilient metal approximately E-shaped in radial cross section. The outer arms of the E have a sinuous configuration and terminate in convex portions which define a primary sealing line when the sealing ring is installed in its cavity. The central arm of the E is a loop having its two sides out of contact with each other. The length of the central arm is approximately equal to the length of the outer arms at the primary sealing line.

D United States Patent 1 1 1111 3,797,836 Hailing Mar. 19, 1974 [5SEALING RING 3,595,588 7/1971 Rode 277/206 R Inventor: Horace P. g, u d.3.633928 l/l972 Smith 277/206 R [73] Assignee: Pressure Science Inc.,Beltsville, Md. Primary ExaminerSamuel B. Rothberg [22] Filed: Sept. 7,1971 Attorney, Agent, or FzrmRoylance, Abrams, Berdo & Kaul [21] Appl.No 177,966

[57] ABSTRACT 521 US. (:1. 277/200, 277/206 R, 277/213, There isdisclosed a Sealing ring of resilient metal p- 277/236 proximatelyE-shaped in radial cross section. The [51] Int. Cl ..F16j 9/20, Flfij15/01) outer arms of the E have a sinuous configuration and [58] Field6'1sfiil;....ii'2'77E06f205;2&200, terminate in convex portions whichdefine a primary 277/236 sealing line when the sealing ring is installedin its cavity. The central arm of the E is a loop having its two [56]Ref ren e Cit d sides out of contact with each other. The length of theUNITED STATES PATENTS central arm is approximately equal to the lengthof the 3,575,432 4/1971 Taylor 277/206 R Outer arms at the pnmary Sealmg3.192.690 1/1965 Taylor 277/205 X 6 Claims, 5 Drawing Figures 1, ,2 7 i7' l 8 a 6 4 6 6 v I Pg- PATENTED MAR 19 I974 INVENTOR HORACE P HALLINGBw fl wzw @444 FIG 4 ATTORNEY5.

SEALING RING This invention relates to metal sealing rings which areespecially adapted for confining fluids at high temperatures andpressures and which remain effective after a large number of pressurecycles and deflections at high temperatures.

As known in the art, there are many applications, such as in pneumaticpiping systems in aircraft, missles and the like wherein it isparticularly desirable or essential to make pipe connections or fittingswith light weight components. Sealing rings designed for such systems,i.e., those wherein the weight of the components to be sealed isminimized, must be sufficiently flexible to follow the large deflectionsin the sealing surfaces and to maintain contact between the seal and thesealing surfaces. The amount of deflection of the sealing surfacesincreases significantly at high temperatures and pressures.

U. S. Pat. No. 3,192,690 discloses a sealing ring of approximate Eshapein radial cross section, the upper and lower arms of the E beingsmoothly sinuous and the back of the E being broken by a central loop orconvolution which forms the short horizontal central arm of the E. Thesealing ring of this patent is particularly useful where there are notlarge deflections in the sealing surfaces e.g., hydraulic systems inwhich the joints are relatively rigid.

U. S. Pat. No. 3,575,432 discloses an improvement over the sealing ringshown in U. S. Pat. No. 3,192,690. This patent relates to a metalsealing ring of approximate E-shape in radial cross section, the outerarms of the E having a sinuous configuration and the outer arms beingfrom about 1.5 3.5 times as long as the middle arm of the E.

It is an object of this invention to provide an improved E-shapedsealing ring having improved deflection capability and longer fatiguelife in high repeated deflection applications.

It is another object of this invention to provide such a seal which isespecially useful in the relatively low pressure systems encountered inmedium to large diameter aircraft pneumatic ducting systems.

These and other objects are accomplished by the practice of thisinvention which, briefly, comprises providing a sealing ring comprisingan integral piece of resilient metal approximately E-shaped in radialcross section. The outer arms of the B have a sinuous configuration andterminate in convex portions which define a primary sealing line whenthe sealing ring is installed in its cavity. The central arm of the E isa loop having its two sides out of contact with each other. The lengthof the central arm is approximately equal to the length of the outerarms at the primary sealing line. This seal gives improved deflectioncapability and longer fatigue life in high repeated deflectionapplications.

The invention will be more fully described by reference to the drawingswherein:

FIG. 1 is a sectional view taken through tubing and showing a couplingwith which the sealing ring of this invention has particular utility;

FIG. 2 is an enlarged view in section taken along line 2-2 of FIG. 1 andshowing the sealing ring of this invention;

FIG. 3 is a partial view in section corresponding to FIG. 2 and showingthe deformation of the tube, coupling and seal ring in the embodiment ofFIG. 2;

FIG. 4 is a partial radial sectional view showing the details of thesealing ring of this invention; and

FIG. 5 is a partial radial sectional view showing a sealing ring asdescribed in U. S. Pat. No. 3,192,690.

Referring to the drawings in detail, in FIGS. 1, 2 and 3 there is showna fluid line coupling and clamping device indicated generally at 1 whichmay be used in combination with the sealing ring of the presentinvention. The coupling assembly shown is commonly referred to as aV-flange coupling which, as known in the art, is used for couplingflanged members such as tube sections in a fluid line. The couplingassembly 1 includes a pair of semi-circular constrictor bands 2 and 2'which are in embracing relation to a tube flange assembly indicatedgenerally at 3, the latter including mating flanges 4 and 4'. Theflanges 4 and 4 are secured as by welding at 5 to tube sections 6 and 6.Opposed annular coaxial grooves or cavities indicated at 7 and 7 areformed in the annular faces of the flanges 4 and 4' having opposed faces8 and 8'. The sealing ring of this invention 16 is interposed betweenand engaged by the flanges 4 and 4 within the cavities or grooves 7 and7 respectively.

The semi-circular constrictor bands 2 and 2 embrace the mating flanges 4and 4' and are adapted, when constricted by take-up connector units 10,to apply axial pressure to the flanges for moving them toward eachother. The constrictor bands 2 and 2' are V-shaped in radial section andinclude radially inwardly diverging side wall portions which function.as jaws for the wedging action against the flanges. The take-upconnector units may be of any suitable design. In the embodiment shownin FIG. 1, the take-up units include an eye bolt 11 having an aperturedhead 12 pivotally mounted on the bolt 13 and a threaded end 14. Theconstrictor bands are drawn toward each other when the nut 15 on end 14is advanced on the bolt.

The sealing ring of this invention is-shown in greater detail in FIG. 4.The outer arms of the sealing ring terminate in convex portions 20 and20. When installed in a cavity, the outermost points 21 and 21' of theseconvex portions contact the wall of the cavity. Therefore, the points 21and 21 define a primary sealing line when the sealing ring is installed.Each of the outer arms has another convex portion 22 and 22' whichdefine a secondary sealing line when the sealing ring is installed in acavity. The two convex portions of each of the outer arms are separatedby concave sections 23 and 23. The central arm of the E-ring comprisestwo elongate portions 24 and 24' which extend in generally parallelspaced side-by-side relation and are interconnected at the terminus 25by a bend. As is seen, the length of the central arm is approximatelyequal to the length of the outer legs at the primary sealing lines. Thecentral arm is generally at least 0.9 times as long as the outer arms.This is in contradistinction to the sealing ring described in U. S. Pat.No. 3,192,690 in which, as shown in FIG. 5, the central arm is shorterthan the length of the outer arms at the primary sealing line. Moreover,the E-seal described in U. S. Pat. No. 3,575,432 has a central arm whichis even shorter with respect to the length of the outer arms at theprimary sealing line.

There should be a space or gap at the back of the E- seal between thetwo ends of the elongate arms 26 and 26' so that there will be nocrushing resulting in high stress when the ring is installed.

The sealing rings of this invention are especially useful in relativelylow pressure applications such as encountered in medium to largediameter pneumatic ducting systems. They have greater deflectioncapability and superior fatigue life when used at very high temperaturesin light weight joints having little rigidity than do seals of the priorart including the seals described in U. S. Pat. No. 3,192,690 and U. S.Pat. No. 3,575,432. Thus, the seals of this invention have operatedwithout failure at over 700,000 pressure impulse cycles of from 400p.s.i.g. at a temperature of 1122F. Under the same conditions oftemperature and pressure, the seals described in U.S. Pat. No. 3,192,690and US Pat. No. 3,575,432 have been found to fail after less than.200,000 pressure impulse cycles. Moreover, the new seals have greatercircumferential flexibility and are therefore able to adapt better towavy surfaces which are common in light weight flanges welded to thinwall ducting.

The seals of this invention may be constructed from thin metal and maybe used without resort to plating with a soft material such as silver asis frequently required with the ring seals of the prior art. Sealingperformance actually improved at high temperature where leakage hasheretofore been most troublesome. Where improved low temperature sealingis desired, a special blistering resistance silver coating may beemployed. Furthermore, the load required to deflect a seal of thisinvention to its installed configuration is lower than that for anymetallic seal presently known.

I claim:

1. In a sealing ring comprising an integral piece of resilient metalapproximately E-shaped in radial cross section, the outer arms of the Ehaving a sinuous configuration and terminating in convex portions whichdefine a primary sealing line when said sealing ring is installed in itscavity, and a central arm of said E being a loop having two elongatedportions out of contact with each other, the improvement wherein thelength of said central arm is approximately equal to the length of saidouter arms at the primary sealing line, whereby said sealing ringpossesses greater deflection capability and superior fatigue life.

2.'The seal according to claim 1 wherein said two elongate portions ofthe central arm of the E extend in generally parallel spacedside-by-side relation and are interconnected at the terminus of saidcentral arm by a bend.

3. The seal according to claim 1 wherein said outer arms of the E aresubstantially symetrical in shape and of essentially equal length.

4. The seal according to claim 1 wherein each of the outer arms ofsinuous configuration include a pair of convex sections with a concavesection between them.

5. The combination of the sealing ring defined in claim 1 with a pair ofrelatively movable flange members which define between them a cavity inwhich high pressures and temperatures are encountered and means forurging the flange members into engagement.

members.

1. In a sealing ring comprising an integral piece of resilient metalapproximately E-shaped in radial cross section, the outer arms of the Ehaving a sinuous configuration and terminating in convex portions whichdefine a primary sealing line when said sealing ring is installed in itscavity, and a central arm of said E being a loop having two elongatedportions out of contact with each other, the improvement wherein thelength of said central arm is approximately equal to the length of saidouter arms at the primary sealing line, whereby said sealing ringpossesses greater deflection capability and superior fatigue life. 2.The seal according to claim 1 wherein said two elongate portions of thecentral arm of the E extend in generally parallel spaced side-by-siderelation and are interconnected at the terminus of said central arm by a180* bend.
 3. The seal according to claim 1 wherein said outer arms ofthe E are substantially symetrical in shape and of essentially equallength.
 4. The seal according to claim 1 wherein each of the outer armsof sinuous configuration include a pair of convex sections with aconcave section between them.
 5. The combination of the sealing ringdefined in claim 1 with a pair of relatively movable flange memberswhich define between them a cavity in which high pressures andtemperatures are encountered and means for urging the flange membersinto engagement.
 6. The combination as defined in claim 5 wherein saidmeans for urging said flange members into engagement includes aconstrictor device at least partially circumscribing said flanges andmeans for tightening the constrictor device radially inwardly around theflange members.